785
FXUS63 KMKX 311411 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
911 AM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Areas of fog are possible (20 to 30 percent chance in any
  given spot) along and west of the Kettle Moraine later tonight
  into early Monday morning.

- Dry conditions with a gradual warming trend through Tuesday.

- Shower and thunderstorm chances are trending upward (50 to 70
  percent or higher) Wednesday and Wednesday night along a cold
  front.

- Below normal temperatures expected Wednesday night into next
  weekend.

&&

.UPDATE...
Issued 911 AM CDT Sun Aug 31 2025

The shallow fog has ended across most areas with daytime
heating. There is an area of clouds over far southwest parts of
the area, and may linger for the rest of the morning, before
mixing out in the afternoon. May see few to scattered diurnal
cumulus clouds develop in the afternoon as well, with light east
winds.

High pressure will linger over the region into Tuesday, which
will continue to bring dry conditions, light winds and slowly
moderating temperatures. The light winds and clear skies
later tonight may allow for another round of shallow fog to
develop along and west of the Kettle Moraine.

Wood

&&

.SHORT TERM...
Issued 255 AM CDT Sun Aug 31 2025

Today through Monday:

Synopsis/Mesoanalysis: A broad area of high pressure is centered
from Lake Huron to the Upper Mississippi River Valley early this
morning, resulting in predominantly clear skies and light/variable
surface winds across most of southern Wisconsin. Model analyses
depict weak convergence in the 925-850 mb layer southwest of
Madison, which has encouraged an area of low stratus development
from roughly Rockford to Monroe. With light surface winds and clear
skies allowing for efficient radiational cooling across the
remainder of the region, areas of ground fog have been noted in
observations along the Kettle Moraine and points west. Anticipate
that pockets of fog will continue through sunrise along the Kettle
Moraine and points west. High pressure will linger over the same
general vicinity through tonight, slowly shifting eastward
during the day on Monday. With the synoptic pattern largely
remaining unchanged, additional areas of fog development will be
possible once again tonight along the Kettle Moraine and points
west. Slow down, use low beam headlights, and allow for extra
following distance if encountering areas of fog through sunrise
this morning and once again tonight.

Rest of Overnight: Will be monitoring obs trends through sunrise
with areas of ground fog developing along/west of the Kettle
Moraine. Pockets of < 1 mile visibilities have already been
noted, though drops have been sporadic/temporary given a very
shallow near-surface moist layer. Given the shallow near-surface
moist layer & attendant brief nature to < 1 mile visibility
drops, tend to think that Dense Fog Advisories won`t be
necessary through daybreak, though trends will nevertheless be
monitored. Should sporadic < 1 mile visibility drops become more
widespread, a Special Weather Statement may become necessary.
Budget a few extra minutes of travel time if taking to the roads
through daybreak. Remember to use low beam headlights and allow
for extra following distance if encountering pockets of ground
fog. Conditions will quickly begin to improve after sunrise.

Tonight: With high pressure still in place regionally and
anticipated clear skies, additional areas of fog development will be
possible along and west of the Kettle Moraine through daybreak. Will
be monitoring trends through the overnight period.

Labor Day: Any early morning fog development will quickly dissipate
following sunrise. Mostly sunny skies are expected, with high temps
topping out in the mid-upper 70s.

Quigley

&&

.LONG TERM...
Issued 255 AM CDT Sun Aug 31 2025

Monday night through Saturday:

Quiet weather continues with large scale ridging remaining in large
part over the region but gradually breaking down and pushing east
while high pressure remains entrenched over the Great Lakes region.
This looks very likely to keep us dry through Tuesday before the
high pressure region fully breaks down and the ridge aloft gets cut
off and pushed out to the east with an upper low digging down
through central Canada.

By Wednesday (trending later Wednesday), we will start to see that
upper trough dig down into the western Great Lakes region with a
developing surface low in Ontario pushing east. With plenty of upper
level support and midlevel moisture this surface low will swing a
front through the region. Still plenty of uncertainty on the actual
timing of this but sometime Wednesday it is expected with rain
likely and with a trend toward a later arrival increasing chances
for storms associated with it. This frontal passage will usher in
much cooler temperatures with rapidly falling heights. While
Thursday may end up fairly cool but quiet another upper low will
swing in behind it for Friday and bring another frontal passage with
showers and storms possible. A brief period of well below average
temps and lows in the 40s would be expected Thursday and Friday
nights. Into the weekend heights will rise back up as the upper low
departs with potential for zonal flow and quieter weather overall.

Kuroski

&&

.AVIATION...
Issued 911 AM CDT Sun Aug 31 2025

The shallow fog has ended across most areas. There is an area
of ceilings around 4000 feet AGL over far southwest parts of
the area, and may linger for the rest of the morning, before
mixing out in the afternoon. May see few to scattered diurnal
cumulus clouds around 3500 feet AGL develop in the afternoon as
well, with light east winds.

High pressure will linger over the region into Tuesday, which
will continue to bring dry conditions and light winds. The light
winds and clear skies later tonight may allow for another round
of shallow fog with 1 to 3 mile visibility to develop along and
west of the Kettle Moraine, affecting the Madison, Janesville
and perhaps Waukesha terminals.

Wood

&&

.MARINE...
Issued 911 AM CDT Sun Aug 31 2025

High pressure around 30.2 inches will linger over the region
into Tuesday, which will continue to bring light winds over Lake
Michigan. Southwest winds will become established Tuesday
night, as low pressure around 29.7 inches develops near Lake
Superior.

The low will slowly move to the Ontario and Quebec border
Wednesday and Wednesday night, dragging a strong cold front
across Lake Michigan in the process. The frontal passage will
result in a gusty northwest wind shift across the waters
Wednesday evening through the day on Thursday.

The current forecast maintains gusts just below gale force
thresholds during this period for the open waters, though
increases to or above gale force may occur in later forecasts. A
Small Craft Advisory will likely be needed for the nearshore
waters, for the gusty winds and building waves.

Showers and thunderstorms will accompany the passing cold front
Wednesday into Thursday. It remains too early to pinpoint any
possibility for waterspouts with this activity, though forecast
trends will be closely monitored. Breezy west winds will
continue through Friday.

Quigley/Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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